The Science Behind Africa’s Great Migration | Asilia Africa (2023)

By Asilia Africa News | 14 June 2018

Every year, millions of hooves drum against Africa’s plains, raising dust and devouring kilometres as wildebeest, zebra and gazelles trek across the Serengeti and the Masai Mara. Called the Great Migration, their odyssey will lead them from drought to water and good grazing, though the way will be fraught with peril.

Crocodiles will claim some migrators as they traverse rivers, battling strong currents and the press of their herd’s wet, heaving bodies. Lions, leopards and hyenas will run down their share of prey on the plains. But ultimately, collaboration between the region’s two ecosystems will see the herds through danger and ensure their future. Indeed, these ecosystems support more large mammal species than any other place in the world. And they’ve maintained one of the world’s last remaining migrations of large mammals in a relatively unchanged state since the time of the hunter-gatherers.

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The Ecosystems

Beginning in Tanzania’s Serengeti National Park and heading north into Kenya’s Maasai Mara Game Reserve, the Great Migration runs in a clockwise circle and covers around 2 900 kilometres. The never-ending journey goes from the southeast grassland region, to the northwest woodlands and back again.

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The Southeast Grasslands

The Serengeti’s large herbivores must find the right quality and quantity of grass to support their species. Essentially, the ecosystem of the grasslands produces environmental circumstances that cater perfectly for their needs. More specifically, the ecoregion has the appropriate soil, climate and rainfall.

The grasslands lie just south of the border between Tanzania and Kenya. Over millions of years, the now dormant volcanic crater of Ngorongoro, the Kerimasi Volcano and Mount Lengai all deposited volcanic ash in these soils. When mineral-rich volcanic ash mixes with soils, the end product contains nutrients such as phosphates, nitrates, potassium, sodium and calcium, all of which are needed for the healthy growth of plants.

Also, the soil of the southeastern plains is a shallow, alkaline and very sandy loam. It overlies a calcareous hardpan that was created by the leaching of lime-rich soil. For the most part, the plains are treeless, given that deep-rooted plants and grasses can’t punch through the hardpan. But, the hardpan does allow minerals that would be unavailable in deeper soils to nourish short grasses. These grasses have adapted to the short growing season and heavy grazing of the region.

The Serengeti plains have the virtues of volcanic soils, meaning they’re extremely mineral-rich and fertile. Their short grasses contain much-needed nutrients such as calcium, nitrogen, zinc and sodium. Consequently, the plains are able to support large populations of grazers, giving them the vast quantity of nutrient-rich grass they need to survive.

Climatically, the eco-region is subtropical and averages maximum temperatures of around 26°C. An important feature of this climate is that it makes the region’s rainfall is strongly seasonal, with precipitation peaking during the long-rain period between March and May, and the short rains in November and December. By contrast, the dry season, which lasts from June to October, sees the plains become far too dry to sustain the herds.

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The wet season allows the ecoregion’s incredibly fertile soil to produce the quantity of grass the grazers need. The dry season drives the grazers away and gives the plains a chance to rejuvenate ahead of their return.

Calving Season

The herds gather for calving season in the Serengeti and Ngorongoro Conservation areas of northern Tanzania during January and February. The birthing takes place over a three-week period and will see more than 400 000 calves born some eight months after mating season. The highest calving rate occurs in February, when an average of 8000 wildebeest are born each day.

From April to May, the Serengeti’s southernmost grass plains start to dry out, causing the herds to migrate west and north towards the woodland of the Western Corridor: their transitional grasslands.

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Transitional Grasslands

Rainfall increases and evaporation decreases as the herds march further away from the Crater Highlands. This movement leads them to different soils and grassland. The soils become more mature and deeper. The vegetation shifts to medium-height grasses that grow on lime-rich soil, underlain by a softer pan that woody roots can penetrate in places. This type of grass receives fairly heavy grazing during the wet season.

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Medium grassland then becomes long, 30cm-high grassland, with bamboo and bluestem grasses being the dominant types. The soil in this leg of the migration is black cotton and still volcanic in origin. The herds graze these grasses on the way to and from the woodland, choosing shorter, more agreeable species beneath the overstory of tall grass. The grasses here are high in magnesium, which is important for lactating females and the growing young.

The Rut

By June the rains stop and the drought of Tanzania’s dry season drives the herds further north. At this time, individual groups gather into larger herds and the migrating wildebeest enter their mating season, also called the rut. Upwards of 500 000 cows will mate over a four-week period.

The last type of soil migrators encounter before reaching the woodlands is the tall, red-oat grassland, which grows on brown calcareous soil. It has a lighter texture and is better drained than the black-cotton variety. The area has a lot of palatable understory grasses, meaning the herds graze moderately here during the dry season.

The Two Rivers

Come July, the herds must wade the Grumeti, the first of two rivers cutting across their path to the woodlands. The Grumeti River is deep in places, particularly if rains have been good. Many animals drown in these waters, having no more to give after weeks spent travelling on ruined limbs and under an unforgiving sun. Some will fall to serrated teeth as crocodiles gorge themselves. Those that survive the water will labour up steep, muddy banks to resume their relentless march, with the constant threat of plains predators dogging their steps.

The Science Behind Africa’s Great Migration | Asilia Africa (3)

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August sees the herds into Kenya and brings the promise of good grazing on the lush plains of the Mara. But first they must flounder in the Mara River’s treacherous waters, their flanks once again exposed to ravenous crocodiles.

The herds will be far smaller after they cross, having lost hundreds of thousands to starvation, malnutrition, exhaustion, predation and drowning. But each precious species will have done enough to survive. The thriving plains of the Mara will sustain them while the south prepares for their return.

The Northwest Woodlands

The Mara’s woodlands flourish on the less mineral-rich soils of the ancient granite shield. The area has a higher rainfall and lower evaporation rate than the hotter, drier short-grass plains, producing a more robust undergrowth. Also, the soils experience rich weathering and weak leaching, which leads to the build up of soluble salts, carbonates and bases. The deeper soils support larger tussock grasses.

But as grass production increases with the rainfall, forage quality goes in the other direction. This factor drives the herds back to the mineral-rich grasslands during the wet season.

Back Again

The short rains arrive in November and December, drawing the herds south to the rejuvenated Serengeti plains. More than 90 percent of the cows are heavily pregnant as the tightly packed herds trek back through wooded country, scattering into widely spaced groups once they reach the open plains.

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The cycle of life will continue as they graze on fresh, sweet grasses and drink at seasonal waterholes, taking in the continent’s goodness ahead of the birthing season. In a short while, new calves will replenish the herds ahead of the next Great Migration.


What causes the Great Migration in Africa? ›

Calving Season

From April to May, the Serengeti's southernmost grass plains start to dry out, causing the herds to migrate west and north towards the woodland of the Western Corridor: their transitional grasslands.

What is the Great Migration in Africa? ›

What is the Great Migration? Throughout the year, East Africa's wide-open grasslands are the setting for the Great Migration as millions of wildebeests, Burchell's zebras, antelopes and other herd animals make the trek from the Serengeti in Tanzania to the Masai Mara in Kenya.

What caused the Great Migration? ›

The driving force behind the mass movement was to escape racial violence, pursue economic and educational opportunities, and obtain freedom from the oppression of Jim Crow.

When was the Great Migration in Africa? ›

The Great Migration in July to November

July through November is traditionally considered the best time to view the Great Migration. Between July and August, the wildebeest move en masse into Kenya's Maasai Mara, crossing the Mara River in staggering numbers.

How did the great migration affect life for African? ›

The Great Migration created the first large, urban black communities in the North. The North saw its black population rise about 20 percent between 1910 and 1930.

What were the effects of migration in Africa? ›

The effects of migration on reproduction in the family during the colonial period include 17 extremely low fertility rates, 2) widespread domestic instability, and 3) exacerbation of moral decadence.

What was the most interesting thing about the Great Migration? ›

Not only is it the world's largest concentrated movement of wildlife, but also the longest in distance; the wildebeest travel over 1,800 miles on their on their 9 month journey. The Great Migration isn't a singular event—it's a yearlong cycle, a voyage driven mainly by food and water availability.

What is the biggest legacy of the Great Migration? ›

The Great Migration also began a new era of increasing political activism among Black Americans, who after being disenfranchised in the South found a new place for themselves in public life in the cities of the North and West. The civil rights movement directly benefited from this activism.

What was the Great Migration and why is it important? ›

The Great Migration arguably was a factor leading to the American civil rights movement. Great Migration, in U.S. history, the widespread migration of African Americans in the 20th century from rural communities in the South to large cities in the North and West.

What were the push and pull factors of the Great Migration? ›

A variety of push factors and pull factors were the cause of this massive migration. Blacks were “pushed” by Jim Crow law, rampant discrimination, segregation, and disenfranchisement, and lack of employment in the South and “pulled” by growing employment rates, industrialism and relative tolerance in the North.

Who first migrated out of Africa? ›

Who left Africa first? Homo ergaster (or African Homo erectus) may have been the first human species to leave Africa. Fossil remains show this species had expanded its range into southern Eurasia by 1.75 million years ago.

When did the Great Migration end and why? ›

Its mission over, the migration ended in the 1970s, when the South had sufficiently changed so that African-Americans were no longer under pressure to leave and were free to live anywhere they chose.

Did humans migrate Africa? ›

Between 70,000 and 100,000 years ago, Homo sapiens began migrating from the African continent and populating parts of Europe and Asia.

What was a negative effect of the Great Migration? ›

Previous research had shown an increased risk of both adult and infant mortality among the African Americans who migrated out of the South. Vu probed further, examining the links between migration and low birth weight, as well as the connection between migration and mental health disorders.

What impact did the Great Migration have on mortality of African Americans? ›

The Great Migration—the massive migration of African Americans out of the rural South to largely urban locations in the North, Midwest, and West—was a landmark event in U.S. history. Our paper shows that this migration increased mortality of African Americans born in the early twentieth century South.

Why did World War 1 lead to a great migration for African Americans? ›

Arguably the most profound effect of World War I on African Americans was the acceleration of the multi-decade mass movement of black, southern rural farm laborers northward and westward to cities in search of higher wages in industrial jobs and better social and political opportunities.

Why did early humans migrate out of Africa? ›

Most likely, a change in climate helped to push them out. Experts suggest that droughts in Africa led to starvation, and humans were driven to near extinction before they ever had a chance to explore the world. A climate shift and greening in the Middle East probably helped to draw the first humans out of Africa.

What are the 5 effects of migration? ›

What are the impacts of migration on the destination location?
  • Workers will work for low wages and are prepared to do jobs that local people do not want.
  • Increased cultural diversity.
  • Skills gaps are filled.
  • Boost to the local economy.
  • Government tax revenues increase.

What are two impacts of migration? ›

Migrants eventually induce social, economic, and political problems in receiving countries, including 1) increases in the population, with adverse effects on existing social institutions; 2) increases in demand for goods and services; 3) displacement of nationals from occupations in the countryside and in the cities; 4 ...

How did the Great Migration lead to the civil rights movement? ›

It finds that Black in-migration increased demand for racial equality and encouraged pro-civil rights activism in non-Southern counties. These effects were not only driven by Black voters, but also by progressive segments of the white population, who became aware of the brutal conditions prevailing in the South.

How did the Great Migration affect the economy? ›

They moved to cities like Detroit, Baltimore, and Chicago in what came to be known as “the Great Migration.” And indeed, they did improve their economic standing, with some families doubling their earnings. But opportunities to move up the ladder would dwindle for the generations that followed.

When did Africans migrate to the United States? ›

Africans came to the New World in the earliest days of the Age of Exploration. In the early 1500s, Africans trekked across the many lands in North, Central, and South America that were claimed by Spain, some coming in freedom and some in slavery, working as soldiers, interpreters, or servants.

Who was involved in the Great Migration? ›

The Great Migration, sometimes known as the Great Northward Migration or the Black Migration, was the movement of 6 million African Americans out of the rural Southern United States to the urban Northeast, Midwest, and West between 1910 and 1970.

What are 5 pull factors of migration? ›

The important factors which motivate people to move can be classified into five categories. They are economic factors, demographic factors, socio-cultural factors, political factors and miscellaneous factors.

What is the evidence for the out of Africa theory? ›

Scientists have now dated the skull as being 36,000 years old. The great similarity of this skull to skulls of the same age from Eurasian finds confirms the "Out of Africa"-hypothesis. Modern humans broke out of their place of origin around 40,000 years ago - from Africa south of the Sahara - and populated the world.

Could other human species still exist? ›

The last “sympatric” humans we know of were Neanderthals, who became extinct only about 30,000 years ago. Since stable separation of parts of the species is the key factor for the formation of new species, we can say that a new split of our species is impossible under current circumstances.

What part of Africa did humans start? ›

A new study suggests that the earliest anatomically modern humans emerged 200,000 years ago in what was once a vast wetland that sprawled across Botswana in southern Africa. Later shifts in climate opened up green corridors to the northeast and southwest, leading our ancestors to spread through Africa.

Was the great migration caused by the Great Depression? ›

During the Great Depression, hundreds of thousands of African-American sharecroppers who fell into debt joined the Great Migration from the rural South to the urban North. According to Greenberg, by 1940 1.75 million African Americans had moved from the South to cities in the North and West.

What is the largest black city in US? ›

In 2020, the largest cities which had a Black majority were Detroit, Michigan (population 639K), Memphis, Tennessee (population 633K), Baltimore, Maryland (population 586K), New Orleans, Louisiana (population 384K), and Cleveland, Ohio (population 373K).

How often does the great migration happen? ›

Every year, more than 2 million animals (wildebeest, zebra, and gazelle) migrate in a clockwise direction across the ecosystems of the Serengeti (Tanzania) and the Masai Mara (Kenya).

What color was the first human? ›

From about 1.2 million years ago to less than 100,000 years ago, archaic humans, including archaic Homo sapiens, were dark-skinned.

What race was the first human? ›

Evidence still suggests that all modern humans are descended from an African population of Homo sapiens that spread out of Africa about 60,000 years ago but also shows that they interbred quite extensively with local archaic populations as they did so (Neanderthal and Denisovan genes are found in all living non-Africa ...

Who was the first person to ever be born? ›

Adam is the name given in Genesis 1-5 to the first human.

When was the period of great migrations? ›

The Great Migration, sometimes known as the Great Northward Migration or the Black Migration, was the movement of 6 million African Americans out of the rural Southern United States to the urban Northeast, Midwest, and West between 1910 and 1970.

When was the 2nd Great Migration? ›

The Second Great Migration (1940-1970) is considered by some historians as, essentially, the sequel to its predecessor, the Great Migration (1910-1930).

What was the largest migration in African history? ›

In the 360 years between 1500 and the end of the slave trade in the 1860s, at least 12 million Africans were forcibly taken to the Americas - then known as the "New World" to European settlers. This largest forced migration in human history relocated some 50 ethnic and linguistic groups.

What was the period of the Great Migration? ›

The relocations of African Americans have been among the most consequential migrations in American history. Historians refer to one sequence as the Great Migration, referring to the exodus of more than seven million people from the South to states in the North and West in the decades between 1910 and 1970.

Which of the following was a result of the Great Migration? ›

Which of the following was a result of the Great Migration? African Americans who had participated in the migration still experienced discrimination but fewer injustices than before.

Who started the migration period? ›

The beginning of the period is widely regarded as the invasion of Europe by the Huns from Asia in about 375 and the ending with the conquest of Italy by the Lombards in 568, but a more loosely set period is from as early as 300 to as late as 800.

What is the largest Black city in US? ›

In 2020, the largest cities which had a Black majority were Detroit, Michigan (population 639K), Memphis, Tennessee (population 633K), Baltimore, Maryland (population 586K), New Orleans, Louisiana (population 384K), and Cleveland, Ohio (population 373K).

What state has the most African Americans? ›

2020 census (single race)
% Black or African- American aloneRankState or territory
76.0%1Virgin Islands (U.S.)
44.17%2District of Columbia
53 more rows

Which African country migrates the most to America? ›

Countries with the most immigrants to the U.S. are Nigeria, Egypt, Ethiopia, Ghana, South Africa, Somalia, Eritrea, and Kenya.
Metros with largest African-born population (2010 Census)
Metropolitan areaAfrican population% of total metro population
Washington, DC, MD-VA-WV171,0002.9
9 more rows

Where do Africans migrate the most? ›

More than half of African migrants migrate across African countries, while around one of every four migrants has Europe as a destination region. Among the macro-regions, Eastern and Western Africa host the largest number of migrants, together accounting for almost 60 percent of all international migrants in Africa.

Which African country migrates the most? ›

63.0% of migration was estimated as taking place intra-regionally, while 24.8% of migration was to high-income OECD countries. The top ten migration corridors were 1. Burkina Faso–Côte d'Ivoire, 2. Zimbabwe–South Africa, 3.
By countryUnited States
Nigeria280 000
Ethiopia220 000
Ghana160 000
Kenya120 000
6 more rows

What were the negative effects of the Great Migration? ›

Previous research had shown an increased risk of both adult and infant mortality among the African Americans who migrated out of the South. Vu probed further, examining the links between migration and low birth weight, as well as the connection between migration and mental health disorders.


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